Heavy rains delayed Wellington’s advance until early December. He had 36,000 British, 23,000 Portuguese and 4,000 Spanish infantry in France: Soult had slightly more men. Another 40,000 Spaniards had been left behind because Wellington feared that they would take revenge for the atrocities and privations inflicted on Spain by the French over the previous six years. This would cause the French civilian population to resist, guaranteeing the failure of Wellington’s invasion.
On 21 November Wellington told Lord Bathurst, the Secretary of State for War, that:
our success, and everything, depends upon our moderation and justice, and upon the good conduct of our troops. I despair of the Spaniards. They are in so miserable a state, that it is really hardly fair to expect that they will refrain from plundering a beautiful country, into which they enter as conquerors; particularly adverting to the miseries which their own country has suffered from its invaders. Without any pay and food, they must plunder, and if they plunder, they will ruin us all.
Wellington also had problems with the Spanish government. Charles Esdaile notes that ‘it remained hard to discount the possibility of a complete rupture in relations.’
Wellington’s army was in a position where it was safer to advance than to remain stationary. It was in a narrow salient with the coast to its west, the Nive to its east and the River Adour to its north. The two rivers met at the city of Bayonne.
Wellington’s plan was that part of his army, commanded by Sir Rowland Hill, would cross the Nive and advance on Bayonne. The rest of the army, under Sir John Hope, would remain on the west bank of the Nive and also advance north.
The French had destroyed the bridges across the Nive south of Bayonne. However, there were three bridges in Bayonne, allowing Soult to concentrate his army against either Hill or Hope in an attempt to defeat the enemy in detail.
Hill’s corps waded across the Nive at three fords near Cambo, meeting little resistance. Other Allied troops, commanded by Lord Beresford, crossed the Nive via a pontoon bridge further north. A bridge at Ustaritz was repaired, so the two corps could remain in contact with each other.
Hope advanced to Bayonne, expecting the French to remain in their fortifications. At about 9:00 am on 10 December, however, a French attack from Bayonne took him by surprise. There were two roads heading south from Bayonne between the Nive and the sea. One headed diagonally towards the sea and then south close to the coast. The other, to Ustariz, remained close to the Nive. Widespread woods and marshes meant that most of the fighting was near the roads.
The initial French attack along the coast road forced Hope’s pickets back three miles. Fierce fighting at a large farmhouse called the Chateau Barrouillet initially went badly for the Allies, who were outnumbered three to two. However, reinforcements arrived and stabilised the line. Both sides lost about 1,500 to 1,600 men killed, wounded and captured.
Meanwhile on the Ustariz road the Light Division was forced to retreat two miles to a strong defensive position at the Chateau and Church of Arcangues. As well as the two buildings, there was a hill with hedges and stone walls at its summit and marshy ravines at both ends. The Allies were able to hold off the enemy, inflicting over 400 casualties for the loss of 225 of their own men.
The French suffered slightly more casualties over the two actions, but they received a heavier blow in the evening. A German unit in French service, the Nassau Regiment, followed secret orders issued to its commander, General August von Kruse, by the Duke of Nassau after Napoleon’s defeat at Leipzig to defect to the Allies. Soult lost 1,400 men directly. He and Marshal Louis Gabriel Suchet, commanding French troops in north west Spain, decided that they must disband all their German units, totalling 3,000 men.
Soult now switched his attention to Hill’s corps on the east bank of the Nive, which he attacked at St Pierre on 13 December. Rain had caused the Nive to rise, sweeping away the Allied pontoon bridge the day before.
The Allied troops were at first pushed back in a bloody battle. However, once Hill learnt that reinforcements were on their way across the now repaired pontoon bridge he launched a counter-attack. The French were forced back to Bayonne. They lost 3,300 men killed, wounded and captured against 1,775 Allied casualties.
Wellington was now able to put artillery on the south bank of the River Adour, stopping traffic along it to Bayonne. This made it impossible to supply both the population and Soult’s army. Consequently he withdrew most of his army from Bayonne on 14 December, although he left a garrison that did not surrender until 27 April, three weeks after Napoleon abdicated.
An unusual feature of these battles was that Wellington left the bulk of the fighting to Hope and Hill, rather than following his usual practice of being at the key point himself. Jac Weller argues that Wellington realised that he would have to appoint somebody to an independent command at some point. The importance of seniority in the British Army meant that it had to be Beresford, who had already commanded at Albuera, Hill or Hope. Weller suggests that ‘at the Nive and St Pierre Wellington tried out the other two as independent commanders without too much risk.’
 Troop numbers are from J. Weller, Wellington in the Peninsula 1808-1814 (London: Greenhill, 1992), pp. 327-41.
 Quoted in Ibid. Footnote 1, p. 326.
 C. J. Esdaile, The Peninsular War: A New History (London: Allen Lane, 2002), p. 479.
 Ibid., p. 481.
 Weller, Peninsula, p. 338.